IMPACTX: An X-Ray Spectral Model for Polar Dust and Clumpy Torus

Abstract We construct a generic X-ray spectral model for the reflection component from the clumpy torus and dusty gas in the polar region (polar dusty gas) in an active galactic nucleus (AGN), designated as Inclusive Spectral Energy Distribution Model of Polar Dust and Clumpy Torus for X-ray (IMPACTX). To calculate the spectra, we utilize the Monte-Carlo-based, three-dimensional radiative transfer code SKIRT. The adopted geometry is the same as that of the IMPACT model, consisting of a clumpy torus defined by Nenkova et al. and a paraboloid-shell polar dusty gas launched at the inner radius of the torus. We discuss the dependence of the X-ray spectrum on geometrical parameters in comparison with the conventional torus-only model (XCLUMPY). As an example, we have simultaneously applied the IMPACTX and IMPACT models to the X-ray and infrared spectra of the nearby Seyfert 2 galaxy NGC 4388, and have found a solution that can well reproduce both spectra. This demonstrates the importance of using both X-ray and infrared data to constrain the nuclear structure of an AGN.